STDs are some of the most difficult diseases in the world to catch. You have to be up close and personal to spread them. Why, then, are they so common? Because people don't know how to treat, prevent, and avoid them.

An STD is any disease that is spread primarily by sexual contact. One partner transmits the disease-causing organism to the other partner during sex (oral/vaginal/anal/etc.). Not all diseases that affect the sex organs are sexually transmitted. Some are not at all connected with sex. Other diseases are simply sexually associated, not transmitted.

To find out more about STDs and testing, contact:

Division of STD Prevention (DSTDP) Centers for Disease Control and Prevention www.cdc.gov/std